Rheostat



May 5, 1925.

E. E. YAXLEY RHEOSTAT Filed 0G17. 16v, 1922 Patented May 5,1925.V i,

UNITED. STATES PATENT OFFICE.-A

ERNEST E. YAXIJEY, OF CHICAGO, ILLINOIS, ASSSIGNOR OF ONE-HALF TO `YA XLEY MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION .OF ILLI- NOIS, AND ONE-RALF TO CARTER RADIO COMPANY, OF

' PORATIQN OF ILLINOIS.

nHEosTAT..

CHICAGO, ILLINOIS, A COR- Application led October 16, 1922. Serial No. 594,710. i

To all whom t may concern:

Be it known that`I, ERNEST E. YAXLEY, citizen 'of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement ,in Rheostats, of which the following is a full, clear, concise, and exact description.

My invention relates to rheostats and has for4 one of its objects the provision of iinproved means which prevents the total ex clusion of resistance when the rheostat hasY been adjusted toits vextreme resistance eX- cluding position. In carrying out this object of the invention there is a resistance engaging contact and a stop which limits the relative movement of the resistance and the contact in the resistance excluding direction, one of the two first Aaforesaid elements-ot' the structure overhanging the terminating portion of the connected ends of the resistance to engage the other of these two elements while a portion 'of the resistance at the connected end thereof yet remains in circuit.

The invention has for another of its objects an improved housing for the resistance and also aEords a suitable guide for the contact element to hold it in contacting relation to the resistance. `In carrying outthis object of the invention the supportl for the resistance is formed with a resistance receiving groove whose side walls preferably serve to position the resistance and desirably projectbeyond the resistance to constitute a guide'for the resistance engaging contact received therebetween. I

The invention will be more fully explained by reference to the accompanying` drawing in which Fig. 1 is a sectional view of the preferred form of the invention taken through the axis of the resistance support which is preferably rotatable; Fig. 2 is a sectional view on lineA 2-2 of Fig. 1 illustrating a part of the structure; Fig. 3 is a view similar to Fig. 2 showing changed positions of the parts; Fig. 4 is a front vlew of the device; Figo l is a diagram illustrating one circuit arrangement pertaining.

to the same; and Fig. 6 is a plan view, partially in section, of the mechanism shown in Figs. 1, 2. 3 and 4.

Like parts are indicated by similar characters of reference throughout the different figures.

The resistance element 1 is disposed with-- .in an-annular groove 2 formed in the .periphery of a circular resistance support 3 which is preferably formed of insulating materlal, t e wlre of the resistance being desirably uncovered. The resistance isillustrated in the form of a coil of wire, though the invention is not to belimited to the shape of the resistance. .As illustrated, the

side walls of the groove engagethe resist:-A

ance to position it. The resistance engaging contact 4 enters the groove and is positioned by and between the outer edge portions of the portions of the side walls of the groove that project beyond the resist-- ance. Thisl Contact 4 land the resistance It servers to limit the movement of the resistance support in a manner to permit total exclusion of the resistance'when the-circuitv aving it is to be opened and to prevent the total exclusion of the resistance when the circuit having'it is to be closed. To this -end one of the two elements 4 or 7, preferably the element 7, carries a portion 8 of insulating material which overhangs a ter minating a portion of the connected end of the resistance with the results that are clearly illustrated in the diagram, Fig.. 5, when the resistance is being adjusted while remaining in closed circuit. The stop 7 has a portion 9,upon its other. side on which the Contact 4 rides when the resistance and contact 'are relatively adjusted to open the circuit containing the resistance and to totally exclude such resistance, the portion 9 being in the same circle with the resistance 1.

Any suitable means may be employed forV mounting kthe -struoture thus far. described. I have illustrated a mounting plate 10 formed with a hole 11 therethrough in which a-bearing 12 is received. This bearing has a head 13 which is larger than' the hole, a clamping plate 14 being interposed between this head and the plate 10 and being brought into clamping engagement with the plate 10 by nlea-nsof the nut 15 which is screwed upon the shank of the bearing'. A shaft 16 is formed with aflange 17 that engages the sha-nk end of the bearing 12, this shaft havinga reduced threaded portion 18 carrying a nut` 19 that presses the plate 20, through which theshaft extension 18 passes,

. against the larger portion of the shaft whereby said shaft and-plate 2() may be turned tof.

gether. This plateis assembled Witlrthe resistance support 3 by means of the screws 21 so that the resistance may be turned with respect to the Contact 4 whenever the shaft 16' is turned. The outer end of the sha-ft is desirably assembled with a knob 22 that is employed for turning it. This knob is pref# erably of insulation, being brought into assembly with the shaft by means of the bushing 23 upon vvhich the knob is threaded and which bushing is placed in fixed relation with the shaft by means of the set screw 24. Said bushing may carry a pointer 25 to indicate to the user the relative positions of the resistance and its contact. 'If desired, the resistance support 3 may have a plate 26 applied thereto upon which may beplaced a spring anchorage 27 that is co-aXial with the shaft 17. A `coiled spring 28 may. have oneend fastened upon theanchorage and its other end stationarily held by a stationary anchorage 29'. The plate 26 may havean ear 30 formed upon its outer end withswhich the live end of 'fthe resistance may be connected, asrillustra-ted clearly in Figs. 1 and 4.

The circuit is continuedgfrom the plate 26 y through the spring 28 tothe support 29 which is unchangeably connected lwith one end of the circuit, as illustrated in Fig. 5, the other end of the circuit being connected wit-h the contact 4 as clearly appears.

i lVhile I have herein shown and particularly described the preferred embodiment of my invention Ido not wish to be limited to theprecise details of 'construction shown as changes may readily be made without (le-I parting from the spirit of my invention, but'havingthus described my invention I claim as new and desire to secure by Letters Patent the following 1. In a rheostatthe combination with a resistance; ofva. contact engaging the resistance, saidcontact and resistance being relatively movable`vv to change the included re ,of the device overhanging a terminating portion of the connected end of the resistance to prevent total exclusion of the resis- 'y tance from circuit. f

In witness whereof, I hereunto subscribe my name'this 13th' day of October A. D.,

ERNEST E; YAXLEY. 

